1. Field of the Invention
The present invention relates to an obstacle guard for a boat motor and, more particularly, to an attachable obstacle guard for a boat motor and, most particularly, to an adjustable obstacle guard fitting various sized boat motors for such use.
2. Background Information
A variety of designs are used for motors which attach to a boat to provide propulsion. Nearly all motors use internal combustion engines as the power source to rotate one or more propellers below water level to move the boat. The most popular motor designs include the outboard motor which removably attaches to the rear or transom of the boat. A housing supports the internal combustion motor at one end, with the propeller, or “prop,” mounted at the opposite end of the housing, below water level. Various drive shafts and gearing are located within the housing to deliver torque from the motor to the propeller. The housing of the boat motor is usually designated as having an upper housing unit, containing a drive shaft connected to the engine, and a lower housing unit, containing a gear assembly and for mounting the propeller. The upper and lower housing units are joined together by bolted flanges for ease of manufacture and servicing. The lower housing unit also includes an external, horizontal cavitation plate above the propeller and an external, vertical skeg or fin extending vertically, below the propeller. Outboard motors range in size from two horse power to several hundred horse power, with an accompanying increase in size and weight. Such outboard motors are designed to pivot at the point of attachment to the transom, in the event the lower unit encounters underwater obstacles while the boat and motor are moving. Collision of the motor's lower unit and propeller with such obstacles, particularly at high speed, can result in costly damage to either or both of these components of the outboard motor.
Another motor design is the so called “inboard/outboard” (I/O) propulsion unit which includes an internal combustion engine mounted interior the boat (the inboard portion), and a stern drive unit with a propeller (the outboard portion), mounted to a gimble in the rear or transom of the boat. The I/O stern drive unit also contains an upper housing unit containing a drive shaft connected to the engine, and a lower housing unit containing a gear assembly and for mounting the propeller. The upper and lower housing units of the stern drive unit are joined together by bolted flanges for ease of manufacture and servicing. The lower unit likewise includes a horizontal cavitation plate above the propeller and a vertical skeg or fin extending below the propeller. A waterproof seal is attached between the gimbal and transom to prevent water from entering the boat around the gimbal. The I/O units are quite powerful and used to propel larger boats at high rates of speed. Again, collision of the I/O motor's lower unit and propeller with underwater obstacles, particularly at high speed, can result in costly damage to either or both of these components of the I/O propulsion system.
Various guard systems have been devised to protect outboard motors and I/O units from damage caused by collision with underwater obstacles. Patents have been granted for several of these invention, including the following: U.S. Pat. No. 2,319,640 by Sink; U.S. Pat. No. 4,565,533 by Springer; U.S. Pat. No. 4,826,461 by Newman; U.S. Pat. No. 5,178,565 by Jacobson; U.S. Pat. Nos. 5,344,346 and 5,515,315 by Griffin; U.S. Pat. No. 5,664,977 by Dinkowitz et al.; U.S. Pat. No. 5,839,929 by Cousins; and U.S. Pat. No. 6,503,110 by Lammli.
The existing motor guards in this technology include various limitations, including that various sizes and models of boat motors each require a guard specifically designed for that size and/or model of boat motor. Applicant has devised a universally adjustable motor guard device that can be used with a wide range of boat motor sizes and/or models.